The present invention relates to a droplet discharging device for discharging liquid drops of a very small amount, an apparatus for manufacturing a microarray and a method for manufacturing a microarray that use this droplet discharging device.
In recent years, decoding the base sequence of DNA and conducting functional analysis of genetic information became an important task, and DNA microarrays have been used as a technique for monitoring the gene expression patterns and screening new genes. With the array, the gene expression quantity is evaluated by preparing a probe DNA, high-density spotting on a substrate such as a slide glass, hybridizing a target DNA having a base sequence complementary with the probe DNA, of the fluorescent labeled target DNA, and observing the fluorescent pattern.
Further, a protein chip in which a protein is applied with a high density onto a substrate by employing the above-described technology has also been developed and used for expression analysis of proteins or analysis of protein interaction.
In order to manufacture such a microarray, a large number of probes have to be placed with a high density on a substrate. A method employing a droplet discharging device, for example, by using an ink-jet system, is such a method for placing a large number of probes on a substrate with a high density.
For example, Japanese Patent Application Laid-open No. 2002-286735 discloses a droplet discharging device comprising liquid supply openings arranged in the form of a matrix and connected with respective channels to a plurality of reservoir chambers arranged in the form of a matrix, wherein the arrangement pitch of the reservoir chambers is larger than the arrangement pitch of nozzle holes. With this droplet discharging device, the problem of increasing the degree of freedom in designing the nozzle spacing and the disposition spacing of the corresponding reservoir chambers was resolved by employing a multilayer configuration of channel substrates forming channels connecting the nozzles and the reservoir chambers.
However, because the channels in such a droplet discharging device have a multilayer structure, there is still space for improvement from the standpoint of device miniaturization.